RODBOLT!!!!! I NEED YOUR HELP 1999 4 STROKE YAMAHA 80hp

[superdave1953]

The top plug fouls after a couple of minutes. The bottom 3 look like new. I was told the thermostat could be stuck open and not allowing the motor to heat up. I replaced that along with the plugs. It ran fine for a short time and then fouled again. I had a buddy check the carbs with a vac gauge. He thinks it is the head gasket leaking water into the cylinder and fouling out the plug. He ran a compression test top to bottom, 135125125125,,,. I hate to tear the motor apart to replace the head gasket if that isnt' the problem. He has always done great for me, but he also is puzzled by this problem. What do you think?

 

[rodbolt]

Re: RODBOLT!!!!! I NEED YOUR HELP 1999 4 STROKE YAMAHA 80hp

have a leak down test done.
is it oil fouled or wet fuel fouled? has the ign coil output voltage been checked ? a leakdown test can show if the ring gaps have rotated and are lined up as well as any cylinder sealing defects that a compression test cannot.

 

[woowoowoo]

Re: RODBOLT!!!!! I NEED YOUR HELP 1999 4 STROKE YAMAHA 80hp

Hey Rodbolt and Everyone Else
I had that 150 Yamaha and it was making oil. Had that overly expensive Ring Free Treatment and then it wouldn't go above 3500 RPM and would stall when powering up. Well, We got the Boat back and took it to Atlantic Marine in Wrightsville Beach, NC. They had it for about 2 hours and Fixed it. The PROBLEM was that Ringfree had clogged one of the injector filter's/ screen. Then I drained out all of the fuel and put in NON ETHENALL( I think that's how you spell it) Fuel and it runs GREAT. Not stalling any more and runs smooth with that fuel. FYI.
Had the boat in the water this weekend and went through a half tank of 93 octane NON- ETHANALL fuel. Plan on installing a 10 micron filter this week.
Take Care
WOOWOOWOO

 

[rodbolt]

Re: RODBOLT!!!!! I NEED YOUR HELP 1999 4 STROKE YAMAHA 80hp

Ring Free was NOT your problem.
your problem is and was a combination of dirty fuel,lack of maint lack of proper fuel filtration and the fact that ethanol is a wonderful organic solvent that attacks almost everything including the normal aluminium oxide found on any non anondized al surfaces ie fuel tanks and certain engine castings.
but ring free is simply a carbon debonding agent and simply cannot clog a filter on its own.
while they had it apart I hope they also replaced the VST pre-filter with the 10 micron one,updated the engine filter to 10 micron and cleaned the VST filter or your gonna see it again.
that white snot stuff they cleaned was a byproduct of the ethanol cleaning varnish,oxides and moisture from your fuel system.
had nothing to do with ring free
93 octane will actually slow this motor down as its desinged to run on 87 octane unleaded fuels with 10% or less ethanol.
Briggs and Stratton sells a nifty little kit to check ethanol concentrations in your fuel.
we are finding concentrations as high as 30% in spots.
I just wonder if one day someone will study how many dollars this Ethanol boondoggle foisted on an ignorant public has actually cost the average US taxpayer.

 

[woowoowoo]

Re: RODBOLT!!!!! I NEED YOUR HELP 1999 4 STROKE YAMAHA 80hp

Rodbolt,
The Ring Free that was used was a much higher concentration than normal and the engine was not properly broken in. We are the second owner of the boat and most if not all of the hours on the engine where at idle or not over over 2k rpm. We think the ring free may have loosened some carbon and that may have clogged something in the injector. Now with the 93 octane, it seems to be running better, We only put in 63 gallons and ran a quarter of that down this week end. Should we just run this tank down and put back 87. What do you think?
WOOWOOWOO

 

[rodbolt]

Re: RODBOLT!!!!! I NEED YOUR HELP 1999 4 STROKE YAMAHA 80hp

trust me, ring free was NOT your problem.
I have seen 2OZ per gallon treatments run for 20 gallons with no problems.
guy misread the label.
we normally shock treat by running 6 gallons of 87 octane mixed with 16 oz ringfree at normal cruise speeds.
its actually reccomended for certain engine conditions.
if you have carbon in the injector screen it came from the brushes on the electric pump motor inside the VST. its a blow through type pump and why VST filter cleaning is periodic maint.
most likly you just got some trash in the system, happens even to the best.
my suggestion is keep the fuel system as clean as possible, we are even starting to remove fuel senders and physically clean tank bottoms of water now.most likly this ride did not turn over fuel very much and with an addition of a different fuel blend on an old fuel blend you got the gas nasties.
looks kinda like gray snot and will pass right through a water seperato,VST but not an injector screen.
seen it a bunch this summer.
our current fuel blend sucks but I am making a killing off it, but its shut my F150 down once and blew up my 175 ETEC.
dunno what its going to do to my 27' albermarle with a pair of 05 MPI 5.7 volvo's.
havent added fuel to it since spring and still have about 150 gallons onboard.
good luck, keep the fuel fresh,turn it over at least every 3 months and pray.
its the best I can reccomend now until we get this waste of money and good corn likker overwith.

 

[pike hunter]

Re: RODBOLT!!!!! I NEED YOUR HELP 1999 4 STROKE YAMAHA 80hp

Rodbolt, I want to let you know that it's always a pleasure to read you're very well explain and clear answers.
Again I will go to bed with something more in my mind.

I wish you and you're family a happy new year

 

[woowoowoo]

Re: RODBOLT!!!!! I NEED YOUR HELP 1999 4 STROKE YAMAHA 80hp

Hey Rodbolt,
You were right about the clogged injecter. Thanks. Next problem. We have a four blade propp on the boat 14X19 and at WOT we are turning 5200 RPM.
What size propp should we be running and which make. I would be ok with a used one also. Do you have any ideas?
Thanks
Woowoowoo

 

[rodbolt]

Re: RODBOLT!!!!! I NEED YOUR HELP 1999 4 STROKE YAMAHA 80hp

no worries, however this thread originated with a carburated F80. nothing to do with injection.
gets a bit confusing especially for those trying to learn,or in my case those trying to remember .
how about you start a new thread and ill give some reccomendations on what I would do if it were mine.